Most of my work is in Torres Strait in collaboration with Traditional Owners, with a focus on stock assessment and harvest strategies for their hand collectable fisheries. I have spent a lot of time underwater collecting data and am now more involved on the other “dark” side, with analyses and data outputs. I never used code before data school.
The Torres Strait ’Beche-de-mer (sea cucumber) Fishery (TSBDM) has become an important source of income for Torres Strait islanders since the early 1990s. While most beche-de-mer species stocks are in good numbers, several species are closed to fishing, or recovering from fishing pressure such as Sandfish, Black teatfish and Surf redfish. This has led to increased fishing pressure on other species, including the Prickly redfish and Curryfish.
Fishery dependent data (logbooks) were introduced to the TSBDMF in December 2017. However, there is considerable uncertainty about the status of many beche-de-mer populations. A stock survey is at present, still the only way to find out the status of fished beche-de-mer populations in Torres Strait. Previous stock surveys have been undertaken in 1995, 2002, 2005 and 2009. The most recent survey was undertaken in 2019/20.
Thank you to Torres Strait Islander fishery representatives, and to all Torres Strait Islanders for regularly hosting us on their land and supporting this research.
Data exists for the TSBDMF from field surveys undertaken in 1995, 2002, 2005, 2009 and now 2019/20. Previously excel has been used for anlayses for stratitfied mean comparisons and stock estimates of species abundance. My goal is to work up the 2019/20 data set and build on previous analyses using R for fishery statistics of CPUE, as well as modelling to look at stock trends.
Stock survey
SCUBA divers surveyed transects for sea cucumbers species in November 2019 and January 2020. Sea cucumbers were recorded and processed, along with a number of environmental indicators and habitat measurement (Table1).
| holothuria_whitmaei | zone | samocc | strata | count_site_id | area_hectare | longitude | latitude | depth_finish |
|---|---|---|---|---|---|---|---|---|
| 6.4523810 | Barrier | 2002 | Reef edge | 25 | 4263.384 | 144.0456 | -10.186410 | 17.7600000 |
| 0.0000000 | Barrier | 2002 | Reef top | 2 | 2599.626 | 143.9492 | -10.411155 | 2.5000000 |
| 8.9285714 | Barrier | 2002 | Reef top buffer (200 m) | 14 | 9341.058 | 143.9927 | -10.300327 | 0.0000000 |
| 0.2604167 | Cumberland | 2002 | Reef edge | 48 | 4679.308 | 143.7410 | -9.996976 | 17.5729167 |
| 2.3148148 | Cumberland | 2002 | Reef top | 54 | 30938.752 | 143.6748 | -10.032286 | 0.3148148 |